Critical and gradual transitions in pattern forming systems

by Golan Bel

at Physics Colloquium

Thu, 05 Nov 2015, 15:30
Physics building (#54) room 207

Abstract

Critical transitions have attracted a great deal of attention due to their relevance to many natural and social systems Much research has been devoted to the characterization and identification of imminent critical transitions In spatially extended systems the dynamics close to and away from the critical point is more complicated due to the expansion shrinking and coalescence of alternative state domains Pattern forming systems introduce additional complexity due to the patterned nature of one of the stable states In this talk I will present several works in which we used the context of drylands vegetation dynamics to study various aspects of this additional complexity: i Using a minimal model we showed that in systems exhibiting a bistability of a patterned state with a uniform state a multitude of intermediate stable localized states may appear giving rise to step like gradual shifts with extended pauses at these states This result suggests that a combination of abrupt shift indicators and gradual shift indicators might be needed to unambiguously identify regime shifts ii The existence of these localized states in models for the dynamics of drylands vegetation and the response of the systems described by these models to local perturbations will be discussed iii We show how a simplified version of a model for drylands vegetation dynamics can explain the emergence and the observed dynamics of the spectacular phenomenon of fairy circles in southern Africa If time permits I will present recent results demonstrating the effects of heterogeneity on the pattern formation survivability and resilience of water limited vegetation Refreshments are served at 3:20pm

Created on 22-10-2015 by Bar Lev, Yevgeny (ybarlev)
Updaded on 22-10-2015 by Bar Lev, Yevgeny (ybarlev)